The other day I decided I needed a mold of a half sphere.
I'd been prowling toy and variety stores to find a child's ball large enough to make what I had in mind.
Surprisingly, it was difficult to find but I finally located one after previously buying three of varying sizes.
I had a used box that was just the right size, but it was rather hole-y.
That's when I got the bright idea to line it with duct tape.
No matter how hard I tried, though, it was impossible to get the tape inside without some seams and wrinkles.
After the duct tape was all in, I coated the inside of the box with a liberal slather of cheap dishwashing liquid. Same thing for the ball I wanted to mold.
I mixed up the plaster and poured it into the box, then positioned the ball half-way in and half-way out.
BUT WHAT I HADN'T THOUGHT OF WAS THAT THE BALL WANTED TO POP UP!
There I was, one hand holding the container that had just held the plaster, the other pushing the ball down to just the right depth in the mold box.
What to do, what to do.
Luckily, I was able to grab a bucket filled with water and put it over the top of the box.
The distance between the top of the ball and the top of the box just happened to be at exactly the right level to keep the ball in place where it should be.
Otherwise, I could see myself sitting in a half crouch, holding down the ball in the mold until the plaster finally hardened.
Meanwhile, in the other hand, I still had the container I mixed the plaster in. (Too bad for that, it went into the trash 'cause I didn't have time to clean it out with water.)
Not impossible, but damned uncomfortable.
Sorry I don't have a picture of the ball or the whole thing when the plaster set.
I did have to wiggle the ball a bit and work it loose before everything really set solid.
I'm happy to report that the duct tape idea worked the box was very easy to dis-assemble and the mold, after a bit of a clean-up on the top surface (I don't care how the outside looks) is a beauty and I'm looking forward to using it.
Even thinking about making others in smaller sizes.
And maybe even a positive of the negative.
Next time, I'll be much wiser about logistics......